Is 80 gallons going to be enough?

Hey I was asked to provide a quote for this customer to clean his roof. I’ve cleaned some smaller roofs before, but this is the biggest one yet, and steepest roof ( a little nervous lol ) the house is about 4,000sqft I was thinking 80 gallons of total mix of 4% but part of me thinks I might need more than 80. What do you guys think? Also any tips ? Or things you see I should be careful of? They have a good amount of bushes and plants around there property so I’m going to have to make sure to keep everything wet and bag the gutters. The only real potential issue is the gutter that drop from the high roof to low roof I feel it could cause run off. In the picture of the front there is also a small section of roof off to the left that you can’t see from the pic. About the same size of the small section on the right.

80 gallons is way more then you need. Maybe 80 gallons total if using a batch mix tank. Get some slo-mo from Pressure Washer Products and use fair amount of it to make sure it doesn’t run down fast. Get some neutralizer also and pre-wet and post rinse the plants with it. I recently found one called post rinse it’s only $11/gallon

I’d say you’re in the ballpark, if you’re talking total mix. I’d wager 30-40 gallons of SH (esp. given how steep it is, a hair more surfactant might be a good idea)

Ya I was thinking 80-100 gallons of total mix unfortunately I will be batch mixing so 32-40 gallons of sh I have cling-on do you guys have better luck with slow mo? How many oz per gallon do you use?

any surfactant is decent, some are better, often preferences play in…whatever you normally use on a house, I’d probably double it, but other guys are going to be a better resource for technical details like that than I would.

1 Like

Id go off what it says on the bottle or look at pressuretek and see , shoot just a small area see how it runs and add more if it doesnt seem enough should find the sweet spot
1oz gallon i thought it was just like elemeator as far as mixing its designed to be better at sticking up there :man_shrugging:

You’re probably going to be right at about 80 on that one. I’d carry about 10gal extra of SH in case you needed to mix up some more just in case but that’s my average looking house and I normally would figure a gal of mix per 50s/f of roof. You’re going to need to put 2 coats on a fair amount of that one, maybe one medium heavy to start and then another lighter one. 4% is right mix if fresh sh. Save the backside of the garage till last because you can get by with3% on that one so if you run a little low on your mix, can add a little water to do it.

Give your first coat plenty of time to work, like 10min. A lot of guys will sit there and keep spraying till black is gone. Do a section, then go do another and then come back. If you’re shooting a 4% you’ll be amazed how much difference it’ll look in 10-15min.

Insider tip here - , if it been dry for a number of days before and/or it’s hot, take your pw and shower some water on it, just get moderately wet, let drain for about 5min, and then start with your mix. Pre-wetting it helps soften it up, so that it absorbs more of your mix.


Racer, Thanks for the tips. I know our locations and experiences levels are different so I’m sure it’s going to take me longer than it would take you but how long would a job like this take you? And what would you charge? My SH costs are killing me right now I’m getting set up with a chemical supplier we’re I can buy bulk…but for this job I’m probably going to have to buy it locally which is expensive.

Also as for setting up a ladder on there deck, it’s composite. I don’t feel comfortable setting up a ladder on it I don’t want it to slip out. I was thinking of laying down some plywood first and setting up on that. What would you do?

Plywood wood slip on the composite easier than the rubber on the base of the ladder I would think :thinking:

Just make sure flat rubber part of foot is down. But If you’re worried I’d just probably laydown a damp, so it wouldn’t slip, folded up towel.

Doesn’t matter too much what your cost is on the SH, you’re only going to use about 40 gal tops. I’d probably be in the $900 - $1000 range.

How long would that take you to do? Obviously your going to be faster than me but I like to time my self compared to very experienced people, so I can gauge my progress. Tanks again for all the help.

I’d probably allow for about 3.5 hours. Front going to take the longest because of needing to reposition ladder a good bit to get the dormers.

1 Like

Right now my SH cost in $9.00 a gallon.


1 Like

Yup it’s horrible. I’m finalizing the details with a chem company who will deliver. 55gal drums to my house for a lot less like 3.50 a gallon shipped but currently I can only get it locally from a pool store for about $9.00 a gallon they come in a 4 pack for $38.00 ( 4 individual 1 gallon jugs) not sure if I will be able to push this job back until I get the delivery or not.

Where the heck you live?

1 Like

Connecticut. I called a few companies that I was recommended on this site but they won’t deliver to a residential property. Commercial only and one company said I needed to have a storage tank on site for them to fill. I got ahold of an agricultural chem company from NY that will deliver to my house. I plan on using them.

Holy expensive